intercept-stdout/test/intercept.js

Hooking Node.js stdout

var expect = require("chai").expect,
    Intercept = require("../intercept-stdout.js"),
    os = require('os');

describe("intercept-stdout", function() {

    describe('when one interceptor are specified', function() {

        it("should capture stdout when initialized and not when it is unhooked", function() {

            // Lets set up our intercept
            var captured_text = "";
            var unhook = Intercept(function(txt) {
                captured_text += txt;
            });

            // Lets try each of these pieces of text
            var arr = ["capture-this!", "日本語", "-k21.12-0k-ª–m-md1∆º¡∆ªº"];
            arr.forEach(function(txt) {

                // Make sure we don't see the captured text yet.
                expect(captured_text).to.not.have.string(txt);

                // send to stdout.
                console.log(txt);

                // Make sure we have the captured text.
                expect(captured_text).to.have.string(txt);

            });

            unhook();
            captured_text = "";

            arr = ["capture-this!", "日本語", "-k21.12-0k-ª–m-md1∆º¡∆ªº"];
            arr.forEach(function(txt) {

                // send to stdout.
                console.log(txt);

                // Make sure we have not captured text.
                expect(captured_text).to.be.equal("");

            });

        });

        it("should modify output if callback returns a string", function() {

            var captured = [];
            var unhook = Intercept(function(txt) {
                var mod = modified[captured.length];
                captured.push(mod);
                return mod;
            });

            var arr = ["capture-this!", "日本語", "-k21.12-0k-ª–m-md1∆º¡∆ªº"];
            var modified = ["print-this!", "asdf", ""];

            arr.forEach(function(txt) {
                // send to stdout.
                console.log(txt);
                // make sure captured doesn't contain the original text
                expect(captured).to.not.contain(txt);
            });

            expect(captured).to.eql(modified);

            unhook();

        });

        it("should do the same for console.error", function() {

            var captured = [];
            var unhook = Intercept(function(txt) {
                var mod = modified[captured.length];
                captured.push(mod);
                return mod;
            });

            var arr = ["capture-this!", "日本語", "-k21.12-0k-ª–m-md1∆º¡∆ªº"];
            var modified = ["print-this!", "asdf", ""];

            arr.forEach(function(txt) {
                console.error(txt);
            });

            expect(captured).to.eql(modified);

            unhook();

        });
    });

    describe('when two interceptors are specified', function() {

        var outputs = [];
        var errors = [];
        var unhook;

        var expectedOutputs = ["capture-this!", "日本語", "-k21.12-0k-ª–m-md1∆º¡∆ªº"];
        var expectedErrors = ["errors here!", "日本語 < huh?", "-k21.12-0k-ª–m-md1∆º¡∆ªº <-- that's some wierd stuff"];

        before(function() {
        	unhook = Intercept(
        		function(txt) {
        			outputs.push(txt);
        		},
        		function(txt) {
        			errors.push(txt);
        		} );

        	expectedOutputs.forEach(function(txt) {
        		console.log(txt);
        	});

        	expectedErrors.forEach(function(txt) {
        		console.error(txt);
        	});

        });

        it("stdout is passed thru first interceptor", function(done) {

        	expectedOutputs.forEach(function(txt) {
        		expect(outputs).to.contain(txt + os.EOL);
        	});

        	expectedErrors.forEach(function(txt) {
        		expect(outputs).to.not.contain(txt + os.EOL);
        	});

        	done();
        });

        it("stderr is passed thru second interceptor", function(done) {

        	expectedErrors.forEach(function(txt) {
        		expect(errors).to.contain(txt + os.EOL);
        	});

        	expectedOutputs.forEach(function(txt) {
        		expect(errors).to.not.contain(txt + os.EOL);
        	});

        	done();
        });

        describe("after the interceptors are unhooked", function() {

        	before(function() {
        		unhook();
        		outputs = [];
        		errors = [];

        		expectedOutputs.forEach(function(txt) {
        			console.log(txt);
        		});

        		expectedErrors.forEach(function(txt) {
        			console.error(txt);
        		});
        	});

        	it("stdout is no longer passed thru first interceptor", function(done) {

        	  expect(outputs.length).to.eql(0);
        	  expect(errors.length).to.eql(0);

        		done();
        	});

        });

      });

});